TABLE 2

Details About Age at Onset, Duration, and Average Daily Dosage of Stimulant Treatment of the 171 Stimulant-Treated ADHD Cases, Separately by Gender

Male (N = 130)Female (N = 41)Total (N = 171)
Age at onset of stimulant treatment (y)
 Mean (SD)10.1 (3.6)10.4 (3.4)10.2 (3.5)
 Median (IQR)9.8 (7.5–12.8)9.4 (7.9–13.3)9.8 (7.5–12.8)
Cumulative duration of stimulant treatment (m)
 Mean (SD)54.4 (37.2)48.3 (37.9)53.0 (37.4)
 Median (IQR)45.9 (27.3–77.0)35.5 (16.9–72.2)44.8 (22.6–76.9)
Average daily dosage (in MEUa)
 Mean (SD)27.8 (11.1)21.3 (7.4)26.2 (10.7)
 Median (IQR)26.6 (20.0–33.1)20.0 (17.3–25.0)24.5 (19.9–31.5)
  • IQR, interquartile range; MEU = methylphenidate equivalent units.

  • a All abstracted stimulant dosages were converted into MEUs with the following formula: 20 mg methylphenidate = 10 mg dextroamphetamine = 56.25 mg pemoline = 10 mg methamphetamine = 10 mg levoamphetamine plus dextroamphetamine.34